Excitation of low-lying levels and giant resonances in 90Zr via 57.5 MeV polarized proton inelastic scattering

Differential cross section and analyzing power angular distributions have been measured for transitions to low-lying bound states with J^π = 2⁺, 3^?, 4⁺ and 5^?, and the giant resonance region from 6 to 27 MeV excitation energy. Collective model calculations using a full Thomas form factor reproduce the data fairly well. The so-called LEOR turns out not to be seen as pure E3 in (p, p′). In the giant resonance region the data do not reveal the presence of a sizeable monopole strength, 10–20% of the energy-weighted sum rule at most. There is strong indication for a mixture of E2 (18% of the EWSR) and E4 (16% of the EWSR). Calculations were also carried out using RPA (1p1h) wave functions. They reproduce the experimental data rather poorly, except for the general behaviour of the cross-section angular distributions.     

(Cyclophan-Metall)-Komplexe: Synthese und Kristallstruktur von ([3.3]Paracyclophan)gallium(I)-tetrabromgallat(III)

Cyclophane-Metal Complexes: Synthesis and Crystal Structure of ([3.3]Paracyclophane)gallium(I) Tetrabromogallate(III) [3.3]Paracyclophane forms 1:1 complexes 2a and 2b with both Ga[GaCl₄] and Ga[GaBr₄]. The crystalline products obtained from toluene solution at room temperature are much less sensitive to air and moisture than most other arene complexes of Ga(I). Solubilities in standard organic solvents are very low, suggesting coordination polymers. The X-ray diffraction analysis of 2b confirms the presence of a two-dimensional network. Both aromatic rings of each cyclophane molecule are η⁶-coordinated from the outer side to Ga(I)-atoms. The position of these metal cations is 2.75 Å above the ring centres. The arene rings are parallel within each cyclophane, but tilted by 48.5° with respect to those of the neighbouring cyclophane. The coordination sphere of the Ga(I) centres is completed by two Br-atoms of two GaBr anions, which link the Ga(I) cations to give … Ga[GaBr₄] Ga[GaBr₄]Ga … strands. The double interconnection of the Ga(I)-atoms gives rise to a two-dimensional sheet structure, which is thus different from the structure of the previously described Ga[GaBr₄] complex of [2.2]paracyclophane, where a three-dimensional network was observed.     

Measurement of the current-phase relation of superconducting atomic contacts

We have probed the current-phase relation of an atomic contact placed with a tunnel junction in a small superconducting loop. The measurements are in quantitative agreement with the predictions of a resistively shunted SQUID model in which the Josephson coupling of the contact is calculated using the independently determined transmissions of its conduction channels.     

Enhanced spontaneous emission from InAs/GaAs quantum dots in pillar microcavities emitting at telecom wavelengths

Optical properties of InAs/GaAs quantum dots in micropillar cavities emitting at 1.3 microm are studied by time-resolved microphotoluminescence. The Purcell effect is observed with an enhancement of the decay rate by a factor of two for quantum dots in resonance with the cavity mode.     

Methodology for the preparation of 2-argininylbenzothiazole

An efficient process to produce kilogram quantities of a key argininylbenzo[d]thiazole intermediate was developed for the preparation of the tryptase inhibitor RWJ-56423. A variety of activated arginine esters and benzo[d]thiazole nucleophiles were evaluated as coupling partners. Our work led to the selection and optimization of an argininyl imidazolide ester and benzothiazol-2-yl MgCl nucleophile. This paper focuses on the preparation, use, and stability of the benzothiazol-2-yl Grignard reagents.     

Identification and relative quantification of adenosine to inosine editing in serotonin 2c receptor mRNA by CE

A new method has been developed allowing the identification and relative quantification of different forms of mRNA after RNA editing. This method was applied to the serotonin 2c receptor mRNA that potentially exhibits 32 different forms after adenosine to inosine editing at five different sites located in a row of 13 nucleotides. CE was used to characterize fluorescently labeled ssDNA molecules on the basis of their conformational polymorphism. The relative amount of these 32 mRNA forms has been estimated by measuring the fluorescence intensity of each individual DNA strand. Accuracy of quantification was established by diluting one form into another or into a mixture of cDNA, showing linear and precise proportion of each form (0.06 相似文献   

Novel ruthenium(II) and zinc(II) complexes for two-photon absorption related applications

Two new fluorene derivatized 1,10-phenanthroline ligands and related tris-chelate Ru(II) or Zn(II) coordination complexes have been synthesised. The linear and nonlinear (two-photon induced fluorescence) photophysical measurements have contributed to highlight the possibility to tune the absorption spectral range and excited lifetime, depending on ligand substitution and nature of the metal. More significantly, the observation of two-photon absorption (TPA) associated with long-lived metal-to-ligand charge-transfer (MLCT) excited states in the Ru(II)-based chromophores, opens a wide range of applications in the near infrared.